How to Save Your Sperm

By Evan Hepler-Smith

July 31, 2017

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CreditCreditNina Berman/Noor, via Redux

Is humanity killing itself off? In a study published last week, a team of epidemiologists found that sperm counts among men in the United States, Europe and Australia have declined by more than 50 percent between 1973 and 2011. Alongside the deleterious effects of cigarette smoke, especially during critical stages of prenatal development, the authors of the study point out that exposure to certain synthetic chemicals has been associated with decreased fertility.

“Men residing in Western countries over the last decades were exposed to new manmade chemicals during their life course, and there is more and more evidence that these chemicals hurt their reproductive function,” one of the study’s authors said in an interview. The authors insist that their findings should drive further research aimed at determining ways to stem the decline, including regulating the chemicals that are contributing to it.

Sounds reasonable. But synthetic chemicals have long been subjects of research and attempted regulation. Beginning in the 1960s, thanks to the efforts of scientists, activists and regulators, chemical products from the pesticide DDT to the all-purpose industrial materials PCBs to the plastics additive BPA, previously understood as unalloyed technological boons, were identified as hazards and partially or fully phased out of use.

Yet even in the rare instances where chemicals are banned outright, they are often replaced by alternatives subsequently found to be just as worrisome. Meantime, more and more synthetic chemicals continue to hit the market. They may draw the most attention when they show up in places like children’s pajamas or macaroni and cheese, but in reality, they are everywhere. Laws such as the recently revised Toxic Substances Control Act in the U.S. give regulators tools to grapple with these substances, but they also highlight the tens of thousands of chemicals that still await assessment.

Why are chemicals studied and phased out at great cost in scientific, advocacy and legal efforts, only to be replaced by alternatives that are just as hazardous?

The problem is twofold. First, there’s the phenomenon called substitution, a basic feature of the science of chemistry itself. For close to two centuries, organic chemists have studied and manipulated the molecular world by swapping chemical groups for each other along the perimeter of carbon-based compounds, like differently shaped and colored Lego blocks. Second, there’s the nature of the chemical industry. Since the early 20th century, American chemical firms have drawn on raw materials derived from oil and natural gas. These were particularly good starting materials for producing things like lubricants, solvents, plastics, fibers — products in high demand from the military, the auto industry and the burgeoning midcentury market for consumer conveniences. Firms made enormous investments in refineries to make oil and gas into certain chemical ingredients, and in factories to convert those ingredients into certain kinds of products. With these expensive, large-scale facilities in place, chemical firms used the magic of substitution to turn out myriad varieties of these basic chemical products to be used in myriad applications.

This way of doing science and doing business was well established by the time toxicologists and environmental activists began to worry about the consequences of synthetic organic chemicals. When they raised the alarm about a particular chemical, chemical entrepreneurs did what the market incentivized and their training equipped them to do: find a slightly different molecule that could do the same thing. As techniques of testing for the presence of chemicals and understandings of their complex, interacting effects have become more sophisticated, the number of individual chemicals of concern has multiplied. Meanwhile, low-cost oil and gas from shale drilling has led to a new boom in chemical production, especially in plastics.

What can be done? Some environmental toxicologists and activists have begun to push for a more categorical approach to safer chemicals, drawing attention to entire classes of chemicals that might be better avoided, as opposed to focusing on particular chemicals whose substitutes might be just as bad.

This would require a whole new way of doing chemistry — not just making safer chemicals, but making safer kinds of chemicals, possibly using entirely new starting materials and processes.

The good news is that some chemists and chemical firms have already begun to push for this under the banner of “Green Chemistry.” Pressure from consumers and retailers for safer products, along with government incentives, have helped to make this a potential path toward a profitable as well as a safer future. But this effort is just the beginning. Old habits, familiar products and existing industrial infrastructure die hard.

Chemists have more than a century of experience in making ingenious use of specific raw materials and in tailoring chemical substances to narrow specifications for desirable products. Can they adapt to a new set of constraints that put long-term safety and sustainability front and center? It is a tall order, but then so was creating the pesticides, plastics, drugs and other chemical building blocks of the modern world. The health of humanity — not just your sperm count — is at stake.

Evan Hepler-Smith (@ehepler) is a Ziff fellow at the Harvard University Center for the Environment. He is writing a book about the history of chemical classification.